Pump or motor wobbler mounting



Sept. 27, 1966 s. s. BAITS 3,274,948

PUMP OR MOTOR WOBBLER MOUNTING Filed July 2, 1964 5 Sheets-Sheet 1 [/0/ 2 71, Mai, man, ya/1M)? {W/Qm/ Sept. 27, 1966 s. s. BAITS PUMP OR MOTOR WOBBLER MOUNTING 5 Sheets-Sheet 2 Filed July 2, 1964 mmm 93 m Sept. 27, 1966 s. s. BAITS 3,274,948

PUMP 0R MOTOR WOBBLER MOUNTING Filed July 2, 1964 5 Sheets-Sheet 5 r ,2 212 \R N 265a 266a 266b 2510 205i) United States Patent 3,274,948 PUMP OR MOTOR WOBBLER MOUNTING Stephen S. Baits, Rockford, Ill., assignor to Sundstrand Corporation, a corporation of Illinois Filed July 2, 1964, Ser. No. 379,821 7 Claims. (Cl. 103-162) The present invention relates to hydraulic energy translating devices and more particularly to multiple piston pumps and motors wherein valving is accomplished by relative rotation between the cylinder block and the valve member.

In conventional axial piston pump designs, an angularly related cam member reciprocates the pistons in a rotating cylinder block and the pistons deliver and withdraw fluid from arcuate ports in a stationary valve plate engaging one end of the cylinder block. The displacement or the amount of flow delivered by the pump may be varied by changing the angular relationship between the cam member and the pistons driven by the cam member, so that as the angle between the cam member and the cylinder block increases in either direction, the displacement of the pump will increase. Problems have arisen in the mounting of the cam member within the housing and prior art mountings for this purpose have been bulky and cumbersome and/or have required diificult and expensive machining operations to properly seat the cam within the housing.

It is therefore a primary object of the present invention to provide a new and improved mounting for the piston reciprocating cam in a hydraulic energy translating device.

Another object of the present invention is to provide a new and improved mounting for the cam in a hydraulic energy translating device having spaced rollers fixed on either the housing or the cam member engaging guide surfaces on the other member. By employing two pairs of rollers, each pair engaging a single Way surface, the device may be operated in opposite directions, with high pressure on either side, and the heavy load carried in an accurately predictable manner divided between the rollers of a pair, and independent of ordinary tolerances. In this manner a full support bearing is provided even though there may be some irregularity in the machined way surface.

A further object of the present invention is to provide a mounting for the cam member which reciprocates the pistons in a hydraulic pump or motor with two sets of rollers and two separate parallel ways engaging the rollers with means on one of the ways for locating the cam member laterally so that only one of the ways accurately locates the cam member laterally. By utilizing this type of way construction, a significant reduction in the machining results as roller locating surfaces need to be machined on only one of the ways. Further, the spaced sets of rollers prevent any lateral tilting of the swashplate regardless of the adjusted position thereof.

Another object of the present invention is to provide a new and improved mounting for the cam member in a reciprocating piston hydraulic unit having rollers rotatably mounted in the housing and way surfaces formed on the cam member for receiving the rollers. In prior art hydraulic units, it has been found difiicult to machine the way surfaces within the housing member as the machine tool must enter the housing from the open end and extend a sufficient distance to machine the ways, which limits the size and type of tool that may be used for this purpose. However, applicant has eliminated this problem by mounting rollers in the housing which are machined before assembly thereto so that only the ways on the swashplate which receive the rollers need be machined and these are easily machined prior to assembly.

A more specific object of the present invention is to provide a variable displacement hydraulic unit having a housing member, a valve element in the housing member having inlet and outlet ports therein, a cylinder block rotatable relative to said valve element and having cylinders therein selectively communicating with said ports during said rotation, pistons slidable in the cylinders, a cam member for reciprocating the pistons, a mounting for the cam member including two bosses in the housing member on the side of the cam member opposite the cylinder block, a shaft mounted in each of said bosses lying in a plane perpendicular to the axis of rotation of the cylinder block, two recesses in each of the bosses, rollers mounted on the shafts in each of the recesses, the shafts being spaced apart on the order of 45 degrees on a circle defined by the pivotal axis of the cam member, two parallel arcuate ways on the cam member each receiving two of the rollers, one of the Ways including a groove having fiat sides engaging the sides of the rollers :in the groove, the other of the ways having only one flat. side whereby the cam member is located by only one of the ways.

Other and further objects and advantages of the present invention will be readily apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIG. 1 is a longitudinal cross sectional view of a hydraulic unit incorporating a preferred embodiment of the present invention;

FIG. 2 is a cross section taken generally along line 22 of FIG. 1 showing the mounting rollers in the hydraulic unit housing;

FIG. 3 is an elevational view of the cam member of the preferred embodiment taken generally on the line 3-3 of FIG. 1;

FIG. 4 is a longitudinal cross sectional view of another embodiment of the present invention in a crosshead type P p;

FIG. 5 is an elevational view of the swashplate in the embodiment of FIG. 4;

FIG. 6 is an elevational view of the end cap of the pump in FIG. 4 showing the mounting ways for the cam member; and

FIG. 7 is a fragmentary cross section taken generally along line 7-7 of FIG. 4.

While this invention is susceptible of embodiment in many diflerent forms, there is shown in the drawings and will herein be described in detail several embodiments of the invention, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. The scope of the invention will be pointed out in the appended claims.

It should be understood that while the hydraulic unit described in this specification is referred to as a pump, that the principles of the invention are equally applicable to a hydraulic unit acting as a motor.

The embodiment of FIGS. 13

Referring now to FIG. 1, the pump housing 10 is a unitary metal casting having a bushing 11 press fitted within a counterbore in one end of the housing 10 for seating the outer race of bearing 12. The bearing 12 supports a pump input shaft 13 within the housing 10. One end of shaft 13 has splines 14 thereon which engage and drive splines in a central bore 16 in a pump cylinder block 17.

The cylinder block 17 is a cylindrical metal casting having axial cylinders formed therein opening directly to face 20 of the cylinder block and communicating with the cylinder block port face 21 through cylinder block ports 22.

Slidably mounted in each of the cylinders 18 are pistons 26 each having a semispherical socket 27 which surrounds and captures a spherical ball 28 of one of a plurality of connecting rods 29. Spherical balls 31 are integrally formed on the other ends of the connecting rods 29 and are seated within semispherical sockets 32 in a unitary annular ring 33. The connecting rods 29 are therefore pivotally connected to both the pistons 26 and the unitary annular ring 33.

The annular ring 33 serves to transfer the camming force from a swashplate or cam member 35 to the piston 26, and the sockets 32 formed in one face thereof lie on a circle drawn about the axis or center of the annular ring 33.

The swashplate or cam member 35 is rotatably mounted in the housing by rollers 40 and 41 rotatably mounted on shafts 42 and 43 fixed in the housing 19, there being two rollers on each of the shafts 42 and 43. The arcuate surface 45 on the back of the swashplate 35 is formed so that the swashplate pivots about point 46.

Referring to FIGS. 1-3 for a more detailed description of the mounting for cam member 35 in the housing, two bosses 100 and 101 formed integrally with the housing 10 have through bores 104 and 105 therein, respectively, which receive the shafts 42 and 43. Set screws 107 retain the shafts 42 and 43 in the housing. Recesses 110, 111, 112 and 113 are formed in the bosses 100 and 101 and receive the rollers 40, 41, 112 and 113, repectively. Each of the rollers has roller bearings 116 therein seated on shafts 42 and 43 so that the rollers rotate with respect to the shafts.

The bosses 100 and 101 are cut away at 120 and 121 so that the cam member 35 will not interfere with the bosses when the rollers are seated in the cam. Each of the rollers rotates about an axis common to one of the other rollers, e.g., rollers 40 and 113, and each of the rollers rotates in a plane common to another one of the rollers, e.g., rollers 40 and 41. For purposes of discussion, the two rollers lying on a common rotational axis will be termed a set of rollers, thus rollers 40 and 113 constitute one such set and rollers 41 and 112 constitute the other set.

Referring now to FIGS. 1 and 3, the rollers rotatably mounted in the housing 10 fit in ways 125 and 126 on the back of the cam member 35. Way 126 consists of a groove in the swashplate having sides 127 and 128 which engage both sides of the rollers 110 and 112 to locate the cam member 35 in a direction parallel to the axis of rotation of the roller. The way 125 has only one shoulder 130 (not for guiding) and therefore the rollers 40 and 41 may have some lateral play therein as they are not captured by the way 125. In this manner only the surfaces 127 and 128' need be machined accurately to seat the cam member 35 in the proper position. Both of the ways 125 and 126 are arcuate in shape so that the cam member 35 will rotate about pivot axis 46. The sets of rollers and the shafts 42 and 43 are spaced sufliciently apart as shown in FIG. 1 to obtain a stable support. As only two rollers are used on each of the way surfaces, they may be designed large enough to sustain a heavy load transmitted by the reciprocating pistons and also to reduce the effects of any irregularities in the way surfaces as the load on the swashplate will be evenly distributed between the rollers even though one of the rollers is riding on a high or low spot on the way surface.

A counterbore is formed in the forward face of the swashplate or cam 35 and defines a camming surface 48 which serves to cam the unitary annular ring 33 and the pistons 26 to drive the pistons to the right and expel fluid from the cylinders 18.

The input shaft 13 rotates the cylinder block 17 along with the pistons and annular ring 33. Under a full displacement of the swashplate member 35 the connecting rods have a substantial angular relationship to the pistons 26 and exert torque producing side loads on the pistons.

Each of the connecting rods 29 exerts a radial force on the pistons 26, the centroid of which, at 46, substantially bisects the axial length of a bearing 17a for the cylinder block 17. In this manner the forces producing tipping moments on the block 17 are balanced about the bearing.

A retaining ring 50 is mounted within the center bore 51 of the annular ring 33 and engages the spherical balls 31 on the connecting rods 29 thereby serving as a piston return mechanism by holding the connecting rods and the annular ring 33 against the swashplate or cam member 35 during the intake stroke of the pump, i.e., when the pistons are moving to the left in FIG. 1. The retaining ring 50 is resiliently urged towards the annular ring 33 by springs 52 mounted in each of the closed ended bores 25 of the cylinder block acting through the semispherical mounting member 54 splined to the input shaft 13. In this manner the springs 52 also serve to urge the cylinder block 17 against a porting and seating surface 60 on valve plate 61 which is bolted to housing 10 by bolts 62. In this manner the cylinder block 17, connecting rods 29 and annular ring 33 rotate as a unit with the input shaft 13.

The port plate 61 has arcuate ports 64 and 65 opening to the seating surface 60 and serve as either high or low pressure ports depending upon the direction of rotation of input shaft 13 and the displacement of swashplate or carn member 35. Communicating with the ports 64 and 65 are inlet or outlet passages 66 and 67 in the port plate 61 and adapted to be connected respectively to a suitable tank (not shown) and the hydraulic load (not shown).

A swashplate return mechanism rotates the swashplate or cam member 35 to full displacement when the chamber 78 and piston 79 is exhausted to tank. The return mechanism consists of a piston 81 urged towards the swashplate by a spring 82 mounted within sleeve 83 fixed within a bore in a boss 85 formed on the upper portion of the housing 10.

An end cap 86 bolted to the left end of housing 10 by bolts 87 supports a shaft seal assembly generally designated by the numeral 88. The shaft seal consists of a first seal member 89 press fitted on shaft 13 and a second stationary seal member 90 mounted within a counterbore in end cap 86 and resiliently urged towards the first seal member 89 by springs 91. Seal members 89 and 90 engage one another at radial surfaces 92 and 93 forming a seal preventing the escape of any hydraulic fluid from the interior of the pump housing. Suitable seals 95 and 96 prevent the escape of fluid along the housing and along the shaft 13 respectively.

The embodiment of FIGS. 47

A somewhat modified form of the invention is shown in FIGS. 4-7. Referring thereto, there is provided a housing 210 closed at one end by an end manifold plate 211 and at the other end by an end closure member 212. A drive shaft 213 is rotatably supported within the housing and carries at one end thereof a crosshead 214, the other end of the shaft being mounted in bearing 215, and the crosshead 214 is rotatably carried by hearing 216. A cylinder block 217 is 'rotatably supported in the housing and carries a plurality of pistons 220 in cylinders 221. The cylinders 221 extend generally parallel to the axis of rotation of the cylinder block but some angularity is permissible and may even be desirable under certain circumstanoes.

To produce rotation of the cylinder block 217, a shaft 222 is splined thereto at 223 and is secured by means of a universal joint 224 to the shaft 213.

To hold the cylinder block 217 against the port plate formed on the inner face of end plate 211, there is pro vided a spring 228 compressed between a step 225 on the shaft 222 and a ring member 226 bearing against the cylinder block 217.

Pivotally connected to each of the pistons 220 are links 230 each having a ball 231 at one end thereof and a second ball 232 is at the opposite end thereof with the balls 232 being pivotally secured to slide members 235 slidably mounted in bores 236 in crosshead 214.

A second series of links 237 are provided with balls 238 and 239 at opposite ends thereof engaging sockets 240 and 241 provided in the slide members and in a rotatable cam plate 242, respectively. The cam plate 242 is rotatably supported by a cam member 250 mova'bly carried on two pairs of rollers or wheels 251a and 25112 bearing respectively against arcuate surfaces 252a and 252b formed on the inner face of end member 212. Movement of the cam member in said path is accomplished by means of a hydraulic piston and cylinder device connected by means of a link 253 to the cam member 250 with the opposite end of the link being secured to piston 254- reciprocable in cylinder 255. Fluid under pressure may be supplied through a port 256 to the cylinder 255 to move the piston 254 to the position shown in the drawing. At its maximum stroke, the cam member bears against an adjustable stop 256 to limit the extent of its movement. Movement of the cam member upon withdrawal of fluid from the cylinder 255 is accomplished through the natural moment thereof tending to move the same toward minimum stroke position.

The side forces or side thrusts which would otherwise be directed against the pistons 220 are for the most part taken up by the slide members 235 operating in their bores 236. Further, relatively large changes in amplitude of reciprocation of the pistons 220 can be accomplished through the movement of the cam member 250 in the manner previous-1y described.

Referring to FIG. 5, the cam member 250 is suitably apertured adjacent the central portion thereof as at 260 to permit the shaft 213 to pass therethrough with appropriate clearance in all positions of the cam member. In order to facilitate mounting of the rollers 251a and 251b, the :back face of the cam member is arcuately curved as seen in the elevation-a1 showing of FIG. 4 and has provided therein four recesses as at 261 respectively for receiving the four adjustment rollers. Each roller is mounted by means of a short shaft or axle 263 appropriately fitted in the cam member 250 and passing through the associated recess 261 centrally thereof with one of the rollers thereon. In a preferred embodiment, the shafts are stationarily mounted, and the rollers are rotatable on the shaft by suitable bearing means not illustrated in: detail.

As seen best in the elevational illustration of FIG. 4, the inside face of the end cover member 212 is arcuately recessed in a manner to appropriately receive the arcuate back face of the cam member 250, and additionally is provided with suitable tracks 265a and 2651; respectively for receiving the rollers 251a and 25117. In the preferred arrangement illustrated, the tracks 265a and 2651) comprise arcuately shaped (FIG. 4) hardened inserts fitted in appropriate recesses 266a and 2661) in the cover member 212, each insert being sunk in its associated recess for approximately one-half its thickness so that approximately one-half the thickness is raised above the inner surface of the cover member 212.

As will appear on viewing FIGS. 5, 6 and 7, the rollers 251a and 25117 not only facilitate pivotal adjustment of the cam member 250 and the tracks 265a and 265b, but also guide the cam member against lateral deviation during pivotal adjustment. To such end, the rollers 251b are formed with arcuately curved peripheries 2510 when viewed as illustrated in FIGS. 5 and 7 and the cooperating track member 265b is arcuately curved in a central portion thereof throughout the length thereof as illustrated at 265C in a manner to fit the periphery of the associated rollers. In view of such interfit, the cam member 250 is restrained against lateral movement during pivotal adjustment. If desired, the rollers 251a and the track 6 265a may be similarly formed, but in the interest of economy they need not be so formed.

It will be understood that the construction described immediately above provides advantages similar to those provided in the embodiment of FIGS. 1 3 in that the cam member 250 is supported for facile adjustment by means of four point engagement between the rollers and associated tracks. This is a distinct advantage over previous arrangements by which arcuate surfaces on the cam member and the housing are i-ntenfitted with only a thin fluid bearing or recirculating bearings therebetween, for the reason that such surf-aces must be necessarily substantially precisely arcuate or the fluid bearing will be penetrated by irregularities in the surfaces, leading to unnecessary wear and possible breakdown, or there will be unintended stresses and strains on the parts involved in view of the load concentrations. With the improved construction herein, minor irregularities lead at most to minor and temporary deviations of contact between the guide surfaces and a single roller while the remaining three rollers may safely take the load.

It will be understood that the tracks 265a and 265b, together with the cooperating rollers preferably provide for pivotal movement of the cam member about a preferred center approximately on the axis of the shaft 213 at the place where the shaft axis penetrates the plane transverse thereto and passing through the centers of the spherical sockets 240 in the slide members 235 so that the forces acting on the cam member through the links 137 are balanced as nearly as possible. It will be understood that it is difficult to mount the cam member for pivotal movement about such a center since it is inconvenient to position a pivot shaft through the middle of the shaft 213 and if trunnions are provided at the proper place then long yoke arms are required for mounting the cam member and this leads to a cumbersome construction. Further, the trunnions would tend to interfere with proper location of bearing 116.

While the embodiments illustrated herein utilize two pairs of rollers symmetrically disposed, it should be understood that if the pump or motor is used under circumstances where only one side will ever be pressurized, then rollers mounting the cam may consist of a pair as shown on the high pressure side and only one located on the low pressure side. Moreover, the rollers may be of different sizes where they take different mean effective loads as such a pro-vision may reduce space and weight where such limitations are stringent. Further, roller axles on opposite sides need not be coaxial.

I claim:

1. A variable displacement hydraulic unit, comprising: a housing member, a valve element having inlet and outlet ports therein, a cylinder block rotatable relative to said valve element and having cylinders therein serially communicable with said ports during said rotation, pistons slidable in said cylinders, a cam member pivotally mounted in said housing; a pivotal mounting for said cam member including two spaced arcuate ways on one of said members, said ways lying generally .in a common arcuate plane, spaced shafts mounted on the other of said members each extending over both of said ways, said shafts being spaced apart on a circle defined by the pivotal axis of said cam members, rollers mounted on each of said shafts and engaging said ways, means on one of said ways for preventing relative lateral movement of the rollers engaging said one way, and said other way having a surface permittir relative lateral movement of the rollers engaging said other way whereby only one of the ways defines the lateral position of the came member in the housing.

2. A variable displacement hydraulic unit as defined in claim 1 wherein one of said ways includes a groove in said cam member having fiat sides, the sides of the rollers engaging said one way being flat and sized so that the rollers fi-t closely on the flat sided way.

3. A variable displacement hydraulic unit as defined in claim 1 wherein one of said ways includes a groove in said housing member having an arcuate cross section, said rollers engaging said one groove having an arcuate cross section, said other way having an arcuate planar engaging surface, and said rollers engaging said other way having a complementary cylindrical surface whereby the curved way and rollers defined the lateral position of the cam member in the housing.

4. A variable displacement hydraulic unit, comprising: a housing member, a valve element in said housing having inlet and outlet ports therein, a cylinder block rotatable relative to said valve element and having cylinders therein serially communicable with said ports during said rotation, pistons slidable in said cylinders, a cam member for reciprocating said pistons, a mounting for said cam member including two bosses in said housing member on the side of said cam member opposite said cylinder block, a shaft mounted in each of said bosses lying in a .plane perpendicular to the axis of rotation of said cylinder block, two recesses in each of said bosses, rollers mounted on said shafts in each of said recesses, said shafts being spaced apart at least 45 degrees on a circle defined by the pivotal axis of the cam member, two parallel arcuate ways on said cam member each receiving two of said rollers, one of said ways including a groove having flat sides engaging the sides of the rollers in said groove, the other of said ways having only one flat side whereby the cam member is located laterally by only one of the ways.

5. A variable displacement hydraulic unit, comprising: a housing member, a valve element in said housing member having inlet and outlet ports therein, a cylinder block rotatable relative to said valve element and having cylinders therein serially communicable with a port during said rotation, pistons slidable in said cylinders, a cam member for reciprocating said pistons, a mounting for said cam member including four recesses in said cam member, a shaft mounted in each recess, a roller mounted on each of said shafts, each of said rollers being rotatable about an axis common to one of the other rollers and being rotatable in .a plane common to another one of the rollers, two of said rollers in said common plane having a curved cross-sectional surface, the other two rollers in the other common plane having flat cross-sectional surfaces, two parallel arcuate ways in said housing member each receiving two of said rollers, one of said ways including a groove having a curved cross-sectional surface contiguous to the curved surfaces on said rollers, the other of said ways having a flat cross-sectional surface engaging said surfaces on the flat rollers.

6. A variable displacement hydraulic unit, comprising: a housing member, a valve element having inlet and outlet ports therein, a cylinder block rotatable relative to said valve element and having cylinders therein serially communicable with said ports, pistons slidable in said cylinders, a cam member for reciprocating said pistons, a pivotable mounting for said cam member in said housing including two parallel arcuate ways on said cam member on the side of said cam member opposite said pistons, two rollers engaging each of said ways and being rotatably mounted within said housing member to adjustably and pivotally support said cam member, one of said ways including a groove having fiat sides engaging the sides of the rollers in said groove, the rollers engaging said one way having flat sides engaging the sides of the associated groove, and the other of said ways having a surface permitting relative lateral play of the rollers engaged therewith.

7. A variable displacement hydraulic unit comprising: a housing member, a valve element in said housing member having inlet and outlet ports therein, a cylinder block rotatable relative to said valve element and having cylinders therein serially communicable with said ports during said rotation, pistons slidable in said cylin- 'ders, a cam member pivotally mounted in said housing; a pivotal mounting for said cam member including two spaced arcuate ways on one of said members, said ways being aligned in a common arcuate plane, two spaced pairs of rollers mounted in the other of said members, the rollers in each pair being rotatable about substantially coincident axes, the axis of each pair being aligned on a circle defined by the pivotal axis of the cam member, two of said rollers engaging one of said ways and the other two of said rollers engaging the other of said ways, means on one of said ways for preventing relative lateral movement of the rollers engaging said one way, and said other way having a surface permitting relative lateral movement of the rollers engaging said other way whereby only one of the ways determines the relative position of the cam member in the housing.

References Cited by the Examiner UNITED STATES PATENTS 2,409,185 10/1946 Blasutta l03l62 2,945,449 7/1960 Le Febvre et a1. l03l6-2 2,976,491 1/1961 Wiggermann 103162 3,136,264 6/1964 Wahlrnark 103-162 FOREIGN PATENTS 687,055 5/1964 Canada.

MARK NEWMAN, Primary Examiner.

SAMUEL LEVINE, Examiner.

R. M. VARGO, Assistant Examiner. 

1. A VARIABLE DISPLACEMENT HYDRAULIC UNIT, COMPRISING: A HOUSING MEMBER, A VALVE ELEMENT HAVING INLET AND OUTLET PORTS THEREIN, A CYLINDER BLOCK ROTATABLE RELATIVE TO SAID VALVE ELEMENT AND HAVING CYLINDERS THEREIN SERIALLY COMMUNICABLE WITH SAID PORTS DURING SAID ROTATION, PISTONS SLIDABLE IN SAID CYLINDERS, A CAM MEMBER PIVOTALLY MOUNTED IN SAID HOUSING; A PIVOTAL MOUNTING FOR SAID CAM MEMBER INCLUDING TWO SPACED ARCUATE WAYS ON ONE OF SAID MEMBERS, SAID WAYS LYING GENERALLY IN A COMMON ARCUATE PLATE, SPACED SHAFTS MOUNTED ON THE OTHER OF SAID MEMBERS EACH EXTENDING OVER BOTH OF SAID WAYS, SAID SHAFTS BEING SPACED APART ON A CIRCLE DEFINED BY THE PIVOTAL AXIS OF SHAFTS AND ENGAGING SAID WAYS, MEANS ON EACH OF SAID SHAFTS AND ENGAGING SAID WAYS, MEANS ON ONE OF SAID WAYS FOR PREVENTING RELATIVE LATERAL MOVEMENT OF THE ROLLERS ENGAGING SAID ONE WAY, AND SAID OTHER WAY HAVING A SURFACE PERMITING RELATIVE LATERAL MOVEMENT OF THE ROLLERS ENGAGING SAID OTHER WAY WHEREBY ONLY ONE OF THE WAYS DEFINES THE LATERAL POSITION OF THE CAME MEMBER IN THE HOUSING. 